Method of refining hydrocarbons by cracking and catalysis



Dec. 1,1942.

W. T. HANCOCK METHOD REFINING HYDROCARBONS BY CRACKING AND CATALYSIS Filed June 18, 1940' M \Q mg a c a a R i k a MW I My i J u 1 Q m fi x. k I Q N\ N h\ W I. lllll k\ HHH m |Illll||l| a K w k g Patented Dee- 1; 942

oer-Ice METHOD OF REFINING HYDROCARBONS BY CRACKING AND CATALYSIS l William T. Hancock, Long Beach, Calif.

Application June 18, 1940, Serial No. 341,129 (01. 196-52) 11 Claims.

This invention has to do with the refining of petroleum hydrocarbons, and relates particularly to an improved method whereby the hydrocarbons may be subjected to conversion in the presence of catalytic material, under conditions conducive to maximum effectiveness of the catalyst and most extensive conversion of the hydrocarbons.

The present method may be characterized as one whereby the hydrocarbons first are heated to a'temperature at which the desired conversion will take place in the presence of a particular catalyst or combination of catalysts, and vaporized hydrocarbons then delivered to a conversion zone wherein mixed liquid and vapor fractions of the hydrocarbons are maintained in intimate contact within a body of materialcontaining the catalyst. The temperature to which the hydrocarbons are heated for treatment in the conversion zone will depend upon, and be-,

come subject to variation in accordance with, the particular catalyst used and the nature of the conversion to be accomplished. Similarly,

the pressures to be employed may vary for this same reason. I have found this method particularly effective for the conversion of the charging stock to high percentage yields of high-octane motor fuels, by subjecting the charging stock to an abnormally high degree of dissociation or cracking to produce a high potential yield of compounds capable of conversion to condenslble cracking and polymerizing hydrocarbons. Accordingly, it will be understood that the invention broadly contemplates the use of any suitable catalyst of the type claimed, since the conditions under which the hydrocarbons undergoing conversion are maintainedin contact therewith-increase and maintain theefilciency ot all such catalysts as well as provide a most favorable relationshipibetween themfand the mixed phase hydrocarbons aflected thereby. Certain catalysts, or combinations of catalysts, may however be regarded as preferred.

As illustrative, the catalyst employed may be selected to accomplish any or a combination or the following types of reactions or efiects, 'all of which are included under the general term conversion; dehydrogenation, dissociation or cracking, isomerization, 'cyclization, alkylation and polymerization. To accomplish dehydrogenation, catalysts such as chromic oxide, nickel mixed with alumina (Al-=03), alumina alone, chromic oxide-phosphoric acid mixture, or phosphoric acid on a carrier, may be employed as the catalyst. The principal cracking catalyst is aluminum chloride, although' some value is found in certain metals such as aluminum, magnesium, nickel, cobalt, copper and iron, and the metal oxides. Reactions of isomerization"'may be catalyzed by chromic acid, aluminum, boron phosphate, and nickel mixed with alumina. Catalysts for cyclization to change chain hydrocare 'bons into ring hydrocarbons, include chromic oxide, alumina at high temperatures, and metals such as tin and lead. At present, the principal alkylation catalysts appear to be sulphuric acid.

aluminum chloride and phosphoric acid.

and vapor fractions of the hydrocarbons in consimilar processes directed to the use of adsorptive' materials are claimed in my copending apof non-adsorptive and adsorptive catalysts, since plication Serial Number 306,345; filed ,November 27, 1939, on Cracking of light petroleum stocks, and another application Serial Number 306,346 filed November 27, 1939, on System for For purposes of distinction and general designation, the particular catalysts mentioned above may be termed non-adsorptive catalysts to distinguish them from the usual adsorptive materials such as fullers' earth, bauxite, Death Valley and Muroc clays, hydrated aluminum silicate, and activated clays ingeneral.

Such adsorptive materials are known and employed gen,-

erally as polymerization catalysts (although other known polymerizing catalysts such as the metal chlorides, and oxides of chromium, molybtive and adsorptive catalysts, as designatedfabove.

Frequently, adsorptive clays are used as a base or carrier for other catalysts. For example, adsorbents of the fuller's earth type may be impregnated with other catalysts such as phosphoric or sulphuric acids, active salts such as aluminum chloride, ferric chloride and zinc chloride, oxides of chromium, nickel and cobalt, and metals including chromium, iron, nickel, copper and aluminum. 4

Among the various possible combinations of catalysts that may be employed, the invention contemplates particularly the use of a suitable catalyst to promote cracking within the conversion none to produce a high yield of low molecular weight compounds reformable into the final product, together with a polymerizing catalyst adapted to convert such lower molecular weight products of dissociation, into higher boiling hydrocarbons within the motor fuel range. For. this purp se, the catalytic material may comprise the combination of a cracking catalyst such as aluminum chloride. and an adsorptive clay, the aluminum chloride acting to promote dissociation,

and the clay to polymerize the products of dissociation to recoverable gasoline fractions. The

- use of aluminum chloride as the cracking catalyst may also serve to considerably reduce the conversion zone temperature required for crackmay be discharged directly into the conversion 7 zone, or first through a separating chamber for the removal of any unvaporized residue. Preferably, the conversion zone comprises a vertically extending chamber containing a stationary foraminate body of the catalytic material, into which the vapors are introduced so as to flow upwardly within and in intimate contact with the material. The vapors in the conversion zone are subjected to partial condensation which, within the broad contemplation of the invention, may be accomplished by any suitable method, and mixed liquid and vapor fractions of the hydrocarbons are maintained in a state of continuous admixture and washing agitation within the body of catalytic material.

The principal advantages of the present method result from the conditions under which the mixed hydrocarbon phases are maintained within the conversion zone. By virtue of their lnti-.,,,

mate contact and constant washing a itation within the catalytic material, the liquid and vapor hydrocarbons approach an equilibrium state favoring the conversion reactions-and at the same time insuring thorough and intimate contact with the catalysis- Simultaneously, the catalyst is conditioned for maximum and .continuedhigh effectiveness by reason of the fact that residual reaction products, such as highboiling polymers and other bodies of a contaminating character.

are constantly being washed out ,of the clay and removed from the conversion zone with the condensate. effective are these conditions that it is found possible to obtain abnormally high and to better advantage from the following detailed description of a typical refining system in which hydrocarbons are subjected to heating and conversion in accordance with the general method outlined above. Reference is made to the accompanying drawing illustrating the system diagrammatically and in flow sheet form.

The charging. stock to be subjected to heatin and conversion may be of any suitable type, although I prefer generally to employ stocks within the kerosene distillate-gas oil range. The charging stock may be discharged by pump II from line H through a suitable preheater II tocoil I! in a cracking still ll, wherein the hydrocarbons areheated to a suitable conversion temperature ranging generally between 800 to l 1"., under suitable pressure, for example to 400 pounds per sq. in. Lower temperatures may be employed where a particular cracking catalyst .in the conversion chamber is capable of effecting the desired degree of cracking at relatively low temperatures. Where the charging stock consists of lower boiling hydrocarbons, as for example withinthe kerosene distillate range, the heated hydrocarbons may be discharged from the cracking still directly through line I! to the conversion chamber it. Ordinarily, however, I prefer to remove all unvaporized residue before passage of the hydrocarbons into the conversion chamber, as by first passing the heated or cracked hydrocarbons through line IT to a separator is, from which the unvaporized residue is withdrawn through line I! and the separated vapors discharged through line 20 to the conversion chamber. If desired. the pressure on the heated hydrocarbons may be reduced in advance of the conversion chamber by regulation of valves II.

The conversion chamber ll comprises a vertically extending shell 22 containing a foraminate body 23 of the previously described catalytic materialwhichmaybeplacedaboveabedofrela-.

'tively coarse stone II within the bottom portion of the chamber. Suitable provision may be made for maintaining a predetermined minimum level L-L' of condensate within the conversion chamber, as by the conventionally illustrated float control ll connected by linkage It with a valve 21 in the condensate outlet line 2! leadingfrom tained in a state of washing agitation'within-a large portion of the body of catalyst. Simultaneously. the hydrocarbons areimdergoing conver sion,i..e. both dissociation and polymerisation,

' with resultant formation of heavy residual bodies.

however are constantly being washed out of the catalytic material by the agitated con- -.densate,- and are removed from the conversion zone through the condensate outlet line 28.

The conversion chamber ll may be maintained at a temperature at which the vapors will undergo partial condensation within the catalytic material, and'particularly is this desirable where partial condensation may not result from other conditions, such as delivery of the vapors directly into a body of condensate within the lower por- The invention will be understood more fully 75 tion of the chamber. Adequate cooling of chamasoauv by a pump ll ifrom'tl ev bottom to the upper interior of the chamber; in previously stated, the temperatures maintained in the conversion chamber ordinarily .will be sumclehtly high to cause a considerable degree of cracking to occur in the presence of the catalyst, and in general this temperature may range, from around 800 to 1100 F., although it is preferred to maintain the vapor outlet temperature not substantially above 900" F., in order to avoid excessive fixed gaslosses. It is found that within the tempera i5 ture range indicated, it is possible to effect simultaneously both substantial cracking and associa- ,tion or polymerization of the cracked products i. e., to produce by the efi'ect of the cracking catalyst, further or more complete dissociation of the vapors heated to cracking temperatur in the cracking still, and to polymerize the resulting reformable hydrocarbons by the effect of the polymerizing catalysts. Valve 3| in the vapor outlet line 32 may be set to maintain any desiredpressure on thehydrocarbons within the conversion chamber. v

' The vapors leaving the conversion chamber through line 32 may be, fractionated or subjected to further treatment by any suitable method. As illustrative, the vapors are shown to be delivered to fractionating column 33 for removal of higher through treating-me wherein the hydrocarbons are heated :to-:cracking tem-v perature. passing vapors i'rom said zo'nelinto a conversion zone containinga' foraminatebody oi' material comprising a non-adsorptive catalyst, and thereby subjecting the hydrocarbons ito'conversion within said materialintroducingg the vapors into a body ,of condensate maintained within the lower intcriorofsaid conversion zone and thereby subjecting mixed liquid and 'va'por fractions oi the hydrocarbons to intimate'contact within said materiaiby 'upward displacement of the condensate therein; so 'that'the' liquid fractions constantly wash themateriali ini the presence of hydrocarbons undergoing'conver'sion and constantly remove residualbodi'csresulting from the conversion, removing" the vapors from said conversion zone, and -separately removing the condensate and its contained 'residual bodies;

2. The method of refining ipetroleuni hydrocarbons that includes, passing i-a stream ofthe hydrocarbons through a 'cracking zone wherein the hydrocarbons are heatedito" cracking temperature, passing vapors from saidf'z'one into a conversion zone containing afi'or'aminate botlyof material comprising a non-adsorptive catalyst',

' and thereby subjecting the hydrocarbons toconboiling fractions above the gasoline range, which are condensed and withdrawn through line 34. The vapors then are taken through line 35 for final condensation in condenser 3i and the product gasoline is collected in receiver 37. Fixed gases and uncondensed vapors are discharged through the valved line 38. Where the hydrocarbons have been subjected to polymerization within the conversion chamber by intimate contact with adsorptive clays oi the character described, the product gasoline is found to be relatively low in sulphur and possessed of water white color stability by reason of the effective removal of polymers and gum forming bodies.

Preferably the condensate'stream and its contained polymers removed from the conversion chamber through line 28, are recirculated for further cracking. The condensate may be returned through line 39 and combined with the charging stock in line H for cracking in coil It, or the condensate may be recirculated through lines 40 and M to an independent heating or cracking coil 42 connecting at its outlet with line It. Instead of introducing the charging stock initially through line H, itv may be fed to the'system through line I! and combined with the recirculated condensate. By thus recirculating the condensate for further cracking, impurities such as sulphur containing compounds and polymers removed from the conversion chamber, are re- -cracked, thus permitting recovery in the system of desirable condensible constituents oi the impurities and providing for elimination of sulphur compounds either as residue from the separator ID, or in the form of fixed gases through the final outlet gas line 38. As illustrated, condensate version within said material; introducingfithe vaporsinto a body of condensate maintained within the lower interior of "said conversion zone and thereby subjecting mixed liquid and vapor removing the vapors from said conversion zone,

and separately removing the condensate and its containedresidualbodies.

3. The method of refining p'etroleumhydrocarbons that includes, passing a stream oi the hydrocarbons through a cracking zone wherein the hydrocarbons are heatedto crackingftemperature, passing vapors from saidzone into aconversion zone containing aforaminate body of material comprising a combination of'difl'erent catalysts one adapted to induce cracking and the other polymerization of the hydrocarhens, and thereby subjecting the hydrocarbons to cracking and polymerization within said ma terial, introducing the vapors'into a body of condensate maintained within the lower interior of said conversion zone and thereby subjecting mixed liquid and vapor fractions of theihydrocarbons to intimate contact within saidmaterial by upward displacement oi'the condensate therein, so that the liquid tractionscons'tantly wash the material in the presence oi! hydrocarbons undergoing cracking andv polymerization I and separately removing thecondensate and its withdrawn from the. fractionating column through line It may be taken to storage through line 44, or recirculated through lines 45 and 4| to the cracking still.

1. The method of refining petroleum hydrocarbons that includes, passing a stream of the 7 and constantly removepoiymers being formed, removing the vapors from said-conversion zone,

containedpolymers. 1 i

4. The method oi. refiningpetroleumvhydrocarbons that includes passing'a stream-10f the hydrocarbons throughv a cracking zone wherein the hydrocarbons are heatedito cracking temperature, passing vapors from-said zone into ia conversion zone containing a foraminate of material comprising a combinations-oi, a metallic cracking catalyst and an absorptive polymerisingcatalysttogetheradaptedtoinduceboth cracking and polymerisation or the hydrocar bons, and thereby subjecting the hydrocarbons to cracking and polymerization within said inaterial, introducing the vapors into a body of condensate maintained within the lower interior or said conversion zone and thereby subjecting mixed liquid and vapor fractions of the hydrocarbons to intimate contact within said material by upward displacement or the condensate maintained within the lower interior of scamversion zone and thereby subjecting mixed liquid andvapori'ractionsoithehydrocarbonstointipolymers being formed, removing the vaporsi'rom therein,sothattheliquldiractionsconstantly washthematerialinthepresence oihydrocarbons undergoing cracking and polymerization and constantly remove polymers being formed, removing the vapors from said conversion zone, and separately removing the condensate and its contained polymers.

5. The method oi refining petroleum hydrocarbons that includes, passing a stream of the hydrocarbons through a cracking lone wherein thehydrocarbonsareheatedtocrackingtemperature,passingvaporsiromsaidzone into a conversion zone containing a ioraminate body or material comprising a combination oi aluminum chloride and adsoiptive clay catalysts together adapted to induce both cracking and polymerization within said material, introducing the vapors into a body of condensate maintained within the lower interior of said conversion zone and thereby subjecting mixed liquid and vapor fractions of the hydrocarbons to intimate contact within said material by upward displacement of the condensate therein. so that the liquid fractionscoustantly wash the material in the presence oi! hydrocarbons undergoing cracking and polymerization and constantly remove polymers being formed, removing the vapors from said converison zone, and separately removing the condensate and its contained polymers.

6. The method of refining pertoleum hydrocarbons that includes, passing a stream 01' the hydrocarbons through a cracking zone wherein the hydrocarbons are heated to cracking temperature, then removing unvaporized residuum from the thydrocarbons and passing the vapors into a conversion zone containing a ioraminate body oi? material comprising a non-adsorptive catalyst, and thereby subjecting the hydrocarbons to conversion within said material, introducing the vapors into a body or condensate maintained within the lower interior oi said conversion zone and thereby subjecting mixed liquid and vapor fractions oi! the hydrocarbons to in timate contact within said material by upward displacement oi! the condensate therein, so that the liquid fractions constantly wash the material in the presence of hydrocarbons undergoing conversion and constantly remove residual bodies resulting from the conversion, removing the vapors from said conversion zone, and separately removing the condensate and its contained residual bodies.

I. The method oi refining petroleum hydrocarbons that includes, passing a stream of the hydrccarbons through a cracking zone wherein the hydrocarbons are heated to cracking temperature, then removing unvaporized residuum from the hydrocarbons and passing the vapors into a conversion zone containing a foraminate body of material comprising a combination of diiierent catalysts one adapted to induce cracking and the .other'polymerization oi the hydrocarbons, and

thereby subjecting the hydrocarbons to-crack ing and polymerization within said material, in-

said conversion none, and separately removing the condensate and its contained polymers.

8. The method of refining petroleum hydro-' carbonsthatincludeapassingastreamoithe hydrocarbons through aheating zone wherein the hydrocarbons are heated to a temperature suitable for catalytic cracking and polymerization of the hydrocarbons, passing vapors irom said zone upwardly within a conversion zone containing a ioraminate stationary body oi material comprising a non-adsorptive cracking catalyst and an adsorptive polymerizing catalyst, and thereby subjecting the hydrocarbons to both cracking and polymerization within said material, partially condensing the vapors and subjecting a considerably large quantity oi the condensate to intimate contact-with vapor fractions within said material so that the condensate is upwardly displaced therein by the vapors and is thereby caused to repeatedly contact and be acted upon by said material, said condensate also serving to constantly wash and remove from the material residual bodies resulting from the cracking and polymerization, withdrawing the vapors from said conversion zone, and separately removing the condensate and its contained residual bodies.

9. The method of reflniiig-petroleum hydrocarbons that includes, passing a stream oi the hydrocarbons through a heating zone wherein the hydrocarbons are heated to a temperature suitable for catalytic cracking and polymerization oi the hydrocarbons, passing vapors from said zone into a conversion zone containing a i'orami-- nate stationary body of. material comprising a combination of diilerent catalysts, one adapted to'induce cracking and the other polymerization of the hydrocarbons. and thereby subjecting the hydrocarbons to both cracking and polymerization within said material, partially condensing the vapors and subjecting a considerably large quantity of the condensate to intimate contact with vapor fractions within said material so that the condensate is upwardly displaced therein by the vapors and is thereby caused to repeatedly contact and be acted upon by said material, said condensate also serving to constantly wash and remove from the material residual bodies resulting from the cracking and polymerization, withdrawing the vapors i'rom said conversion zone. and separately removing the condensate and its contained polymers.

10. The method of refining petroleum hydrocarbons that includes, passing a stream of the hydrocarbons through a heating zone wherein the hydrocarbons are heated to a temperature suitable for subsequent catalytic cracking and polymerization, removing unvaporized residuum from the hydrocarbons, passing the vapors into a conversion-zone containing a foraminate stationary body of material comprising a combination oi diflerent catalysts, one adapted to induce cracking and the other polymerization of the hydrocarbons, and thereby subjecting the hydrocarbons to cracking and polymerization within said material, partially condensing the vapors and troducing the vapors into a body-oicondensate It subjecting a considerably large quantity of the condensate to intimate contact with vapor fractions within said material so that the condensate is upwardly displaced therein by the vapors and is thereby caused to repeatedly contact and be acted upon by said material, said condensate also serving to constantly wash and remove from the material residual bodies resulting from the cracking and polymerization, withdrawing the vapors from said conversion zone, and separately removing the condensate and its contained polymers.

1l.' The method of refining petroleum hydrocarbons that includes, passing a stream of the hydrocarbons through a heating zone wherein the hydrocarbons are heated to a temperature suitable for catalytic cracking and polymeriza tion of the hydrocarbons, passing vapors from said zone upwardly within a conversion zone containing a foraminate stationary body of material comprising aluminum chloride supported on a solid adsorptive carrier, and thereby subjecting the hydrocarbons to both cracking and polymerization within said material, partially condensing the vapors and subjecting a considerably large quantity of the condensate to intimate contact with vapor fractions within said material so that the condensate is upwardly displaced therein by the vaporsand is thereby caused to repeatedly contact and be acted upon by said material, said condensate also serving to constantly wash and remove from the material residual bodies resulting from the cracking and polymerization, withdrawing the vapors from said conversion zone, and separately removing the condensate and its contained residual bodies.

WILLIAM T. HANCOCK. 

